The present invention disclosed herein relates to a radio communication, and more particularly, to a radio frequency identification (RFID) tag.
A radio frequency identifier is a contactless identification system exchanging information by using a radio frequency between an RFID reader and RFID tag. The RFID reader transmits signal toward the RFID tag. The RFID tag receives the signal transmitted from the RFID reader. The RFID tag modulates the received signal and retransmits the modulated signal to the RFID reader. The RFID reader performs a subsequent operation according to the modulated signal received from the RFID tag.
The RFID is largely classified into an active RFID method and a passive RFID method. According to the active RFID method, the RFID tag includes power. The RFID tag operations using a built-in power. According to the passive RFID method, the RFID tag include no additionally power. The RFID reader supplies energy to the RFID tag without contact. The RFID tad operates using the energy supplied from the RFID reader.
The passive RFID method includes a mutual induction method and an electromagnetic method. The mutual induction method is typically used in a lower frequency RFID. According to the mutual induction method, the RFID reader transmits energy of a magnetic field to the RFID tag. According to the electromagnetic method, the RFID reader transmits energy of an electromagnetic wave to the RFID tag.